Stone weathers deteriorates as part of the normal geologic cycle through natural chemical, physical, and biological processes when it is exposed to the environment. This weathering process, over hundreds of millions of years, turned the Appalachian Mountains from towering peaks as high as the Rockies to the rounded knobs we see today. Our concern is that air pollution, particularly in urban areas, may be accelerating the normal, natural rate of stone deterioration, so that we may prematurely lose buildings and sculptures of historic or cultural value.
This religious medieval sculpture, made of sandstone, has been degraded by the acidification of air and rains. Many buildings and monuments are made of stone, and many buildings use stone for decorative trim. Granite is now the most widely used stone for buildings, monuments, and bridges. Limestone is the second most used building stone. It was widely used before Portland cement became available in the early 19th century because of its uniform color and texture and because it could be easily carved.
Sandstone from local sources was commonly used in the Northeastern United States, especially before Nationwide, marble is used much less often than the other stone types, but it has been used for many buildings and monuments of historical significance.
Because of their composition, some stones are more likely to be damaged by acidic deposition than others. Granite is primarily composed of silicate minerals, like feldspar and quartz, which are resistant to acid attack. Sandstone is also primarily composed of silica and is thus resistant. A few sandstones are less resistant because they contain a carbonate cement that dissolves readily in weak acid. Limestone and marble are primarily composed of the mineral calcite calcium carbonate , which dissolves readily in weak acid; in fact, this characteristic is often used to identify the mineral calcite.
Acid precipitation affects stone primarily in two ways: dissolution and alteration. When sulfurous, sulfuric, and nitric acids in polluted air react with the calcite in marble and limestone, the calcite dissolves.
In exposed areas of buildings and statues, we see roughened surfaces, removal of material, and loss of carved details. Stone surface material may be lost all over or only in spots that are more reactive.
You might expect that sheltered areas of stone buildings and monuments would not be affected by acid precipitation. However, sheltered areas on limestone and marble buildings and monuments show blackened crusts that have spalled peeled off in some places, revealing crumbling stone beneath.
This black crust is primarily composed of gypsum, a mineral that forms from the reaction between calcite, water, and sulfuric acid.
Gypsum is soluble in water ; although it can form anywhere on carbonate stone surfaces that are exposed to sulfur dioxide gas SO 2 , it is usually washed away. It remains only on protected surfaces that are not directly washed by the rain. Gypsum is white, but the crystals form networks that trap particles of dirt and pollutants, so the crust looks black. Eventually the black crusts blister and spall off, revealing crumbling stone.
Want to learn more about acid rain and water? Follow me to the Acid Rain website! Biodiversity by the way is important in an ecosystem because it ensures the production of animals. March 11, PM. Posted By: Taylor Fawcett. Great post Sam! I find it so unfortunate that rain is more acidic and less helpful for the environment. Acid rain kill our fresh water supply and creates even more polution than our environment can afford. It is important to also acknowledge the human health affects acidity has on us.
The harm from acid rain isn't direct. Everyday things like walking in acid rain, or swimming in an acid lake, is no more dangerous than walking or swimming in clean water. However, the pollutants that cause acid rain: sulfur dioxide and nitrogen oxides do damage human health.
March 10, PM. Posted By: Cartland Zhou. Nice post, Sam! Acid rain is definitely one of the serious problems in our environment. I was worried about it so I did some research about what we can do individually about acid rain. For example, we should turn off lights, computers, and other appliances when you're not using them. It is just a little thing that we can do for the earth that we live, but if everyone is doing it, it makes a huge difference to it.
Also people are notice the bad conditions we can in. I know that EPA scientists and their colleagues must assess the reductions to make sure they are achieving the results that Congress anticipated when it created the Acid Rain Program in I hope we will really start to protect the earth, the only planet we can live for now, and the mother of every live-thing. March 09, AM. Posted By: Emily D'Arco. Wow, Sam, what a great post!
It's so sad that rain has become more acidic, but I think with much effort and lots of attention, we can reduce the amount of acidity in our rain. Acid rain affects us in our every day lives, in that it pollutes our rivers and oceans and has caused the reduction of the amount of fresh and clean water on our earth today. Look at this link for more specific details! March 08, PM. Posted By: Aurora Tormey.
This is a really great post Sam! I really like how you include in your post what other companies are doing to help decrease the amount of acid in our water systems.
I did some further research and found another surprising contributer to acid rain. Snow, when it accumulates over time, it also releases extremely high amounts of acidity when the now melts. This really harms our environment severely, and I now know what steps to take to improve this situation thanks to jessica's comment. March 08, AM. JavaScript appears to be disabled on this computer.
Please click here to see any active alerts. An ecosystem is a community of plants, animals and other organisms along with their environment including the air, water and soil. Everything in an ecosystem is connected. If something harms one part of an ecosystem — one species of plant or animal, the soil or the water — it can have an impact on everything else.
The ecological effects of acid rain are most clearly seen in aquatic environments, such as streams, lakes, and marshes where it can be harmful to fish and other wildlife. As it flows through the soil, acidic rain water can leach aluminum from soil clay particles and then flow into streams and lakes. The more acid that is introduced to the ecosystem, the more aluminum is released.
Some types of plants and animals are able to tolerate acidic waters and moderate amounts of aluminum. Others, however, are acid-sensitive and will be lost as the pH declines. Generally, the young of most species are more sensitive to environmental conditions than adults.
It weakens them by washing away the protective film on leaves, and it stunts growth. A paper released in the online version of the journal of Environmental Science and Technology in showed evidence of acid rain stunting tree growth. Geological Survey scientist who headed the effort. Acid rain can also change the composition of soil and bodies of water, making them uninhabitable for local animals and plants. For example, healthy lakes have a pH of 6.
As acid rain raises the level of acidity, fish tend to die off. Most fish species can't survive a water pH of below 5. When the pH becomes a 4, the lake is considered dead, according to National Atmospheric Deposition Program. It can additionally deteriorate limestone and marble buildings and monuments, like gravestones.
There are several solutions to stopping manmade acid rain.
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